Microsoft has suffered a major outage that is impacting cloud services including Office365 and Windows Live webmail worldwide.
The outage occurred about 45 minutes ago, according to a graph on the Downrightnow website monitoring service.
Users hit Twitter immediately seeking answers as to the whereabouts of Office365, MSN.com, Live@edu and Windows Live Hotmail.
"We are investigating service interruption. Will update as soon as more details are available or within hour," a Microsoft spokesman said on the official Office365 Twitter feed.
"Intermittent client connectivity causing some users to have trouble with email connection. Continue to investigate," it posted 20 minutes later.
A Microsoft Australia spokesman has been contacted for comment.
The University of Wollongong was one high-profile customer affected by the outage, having moved all student accounts to the Live@edu service last year.
It tweeted a short time ago that all services were "unavailable".
Curtin University CIO Peter Nikoletatos said services had been down at the university for about an hour. The West Australian university adopted Live@edu services two years ago.
"We have discussed it with Microsoft and we're getting advice from them," he said. "We expect that it would be resolved fairly quickly."
Nikoletatos said the University was using "every available communication channel" to keep students updated, including its web portal, Twitter and Facebook accounts.
The University of Western Sydney's IT services desk advised: “We are currently experiencing issues with MyMail student mail system. Technicians are working to resolve this issue.”
It was unclear what caused the outage.
However, speculation was that Microsoft had been caught in a major power cut affecting Southern California, Arizona and Mexico.